Driving means for the slides of machine tools



0. E. ROSEN April 6, 1943.

I DRIVING MEANS FOR THE. SLIDES OF MACHINE TOOLS Filed Oct. :50, 1940 2 Sheets-Sheet 1 5a I III! I I I 1 I I I n 1 m m m M N m I0 F- L A! C u J Y B 0. E. ROSEN April 6, 1-943.

DRIVING MEANS FOR THE 'SLIDES OF MACHINE TOOLS Filed 00%. '30. 1940 2 Sheets-Sheet 2 FIGS;

FIG-2.

INVENTOR.

' OSCAR E.ROSEN ATTORNEYS Patented Apr. 6, 1943 DRIVING MEANS FOR THE SLIDES OF MACHINE TOOLS Oscar E. Rosen, Detroit, Mich. Application October 30, 1940, Serial No. 363,523

2 Claims.

The present invention relates to machine tools and more specifically to operating means for the Work table or other movable elements thereof.

Still more specifically, the invention relates to duplicating machines wherein the work and cutter are moved relatively by automatic means in response to and controlled by the action of a tracer moving over a pattern.

Among the objects of the invention is actuating means for such movable elements, including .a small motor of relatively high speed and speed reducing means which permits the direct drive of such elements even on large machines.

Another object is a speed reducing means which, though non-reversible in ordinary use, nevertheless will slip under extraordinary stresses and thereby act as a safety device.

Other objects will readily occur to those skilled in the art upon reference to the following description and the accompanying drawings in which: I

Figure 1 is a side elevation, partially in section, showing the complete combination.

Figure 2 is a section on line 2-2 of Figure 1.

Figure '3 is a section on line 3-3 of Figure 1.

Figure 4 is a section on line 4-4 of Figure 1.

I Figure '5 is a view similar to Figure 3 but showing a modified structure.

In the drawings, there is indicated at In a rack such as is fixed to the cutter head or other slide of a conventional milling or other cutting machine or machine tool. This rack I is moved longitudinally to move the slide back and forth or up and down, as the case may be, by means of a gear I I, actuated in the conventional machine by suitable gearing, and, in the present case by being fixed to a rotatable shaft I2.

In the present device, the shaft I2 is rotated in one direction or the other by a reversible motor I5 preferably of the type shown and described in United States Patent No. 2,138,208, issued November 29, 1938, or other suitable type. In the patent and in the present device, the motor is indicated as a hydraulic motor controlled through the action of a tracer upon a pattern.

As indicated, the shaft I5a of motor I5, extends from the motor housing into the larger housing I6 where it is keyed in the adjacent end of a sleeve I1, the shaft I5a, sleeve I1, and shaft I2 being in axial alignment.

The opposite end of sleeve I! is enlarged, as shown, and has its outer cylindrical surface somewhat eccentric as indicated at I8, and upon the eccentric portion carries the inner race of antifriction ball or roller bearing I9.

Mounted upon the outer race of the bearing I9 is a thick disc which carries fixed upon its outer periphery a band of friction producing material 2 I, such as a suitable brak lining, and is also provided with a plurality of openings 22 for the reception of studs 23, these and their bushings 24 of friction reducing material being somewhat smaller than the openings 22.

Since the disc 20 and its bearing I9 are mounted upon the eccentric portion I-B of sleeve I1, the disc 20 itself will also be eccentric to the axis of the shaft I 5a. Surrounding the disc 20, but concentric with the shafts I5'a and I2, is a cup member 30, the internal diameter of which is only slightly larger than the over-all diameter of disc 20 and band 2 I, the dimensions of these parts being such that when they are assembled, there will be considerable pressure between thedisc 20 and cup on one side with a slight clearance diametrically opposite. I I I U Cup 30 is fixed by means of suitable screws 3| to a flange32 forming a part of or fixed to shaft I2, being thus a functional part of the latter, while the inner end of the shaft extends into and is piloted by the inner end of sleeve I1, the shaft end, shown at [2a, being surrounded by the small roller bearing I2b.

The shaft I2 is mounted in a suitable bearing 33 in acover plate 34 for housing -I 6. v

Thepins 23, above referred to and of which there are preferably a plurality, six being shown, are provided for the purpose of maintaining the disc 20 against rotation when the motor I5 is operated. These pins 23 are fixed in a second disc 49, rotatably carried upon an inwardly extending flange 4I concentric with the shafts I2 and [5a, the disc being held against axial movement by a collar 42.

This disc 42 is, as shown, a worm gear, having spiral teeth 43 on its periphery, adapted to coact with a worm 44, which Worm is mounted tangentially thereto in the casing I6 in bearings 45 and 46 and operable by means of a hand wheel 41, or suitable driving mechanism.

Bearing 46 is carried in a block 48, movable vertically upon suitable rods 49 and capable of being fixed against upward movement or pressed down tightly by a screw 50. When the screw 50 is tightened downwardly, it will jam together the worm 44 and gear 43 and lock the latter against movement. Slightly loosening the screw 50 will permit rotation of the worm 44 and thereby the gear 43 for a purpose mentioned later. I

Suitable oil passages are shown as providing for the lubrication of the pins 23 in their surrounding bushings.

In order to prevent overrun of the motor I and undesirable movement of shaft Hi, the twoway acting brakeshown in detail in Figure 4 is located between the motor and housing It. In this figure the shaft l5a is shown as carrying a disc or drum 65, against the edge of which act two brake shoes 66, pivoted as at 61 and pressed against the disc 65 by springs 68 acting on their free ends. The spring pressure may be arranged to be adjustablein any suitable manner as by the screws 69.

In the operation of the device, the slide to which it is attached may be moved quickly to its approximate position by loosening screw 50 and turning the hand wheel 41. This causes the ro tation of discs 40 and 20, these being connected by pins 23 and, since disc frictionally engages cup 30, this also rotates and, in so doing, rotates shaft I2.

When the approximate adjustment has thus been accomplished and the screw 50 tightened, thus fixing the pins 23 against movement, the motor I5 is put into operation. With the motor l5 running, the disc 20, carried upon the eccentric 18 will move around upon the inner periphery of cup 30, and, since the disc 20 is fixed against rotation by the pins 23, the cup and the shaft I2 is forced to turn.

If, however, the resistance of the slide, due to any reason whatever, becomes sufficiently great, the friction between disc ZU-and cup 3!) will be overcome and these parts will slip, thereby preventing breakage. Further, with only a slight eccentricity of sleeve l8, the reduction in speed from shaft 15a to shaft [2 becomes so great that a very small motor I5 is capable of exerting enormous torque upon the driven shaft [2.

In applying the device to any machine, the housing [6 or plate 34, or both, will be fixed to any suitable stationary part thereof.

The structure so far described, is, as indicated, particularly suitable for milling machines or the like, and, while such structure may also be used on lathes, it is desirable to modify it somewhat to permit turning the work set up in the lathe quickly and easily. 1 v

Figure 5 shows such a modified structure.

In this figure, the modification is shown to consist in omitting the M and the coacting teeth preferred embodiment, what is claimed is:

1. Speed reducing means for motor driven elements' consisting of a cylindrical cup fixed to the driven element, a disc within said cup and eccentric thereto and arranged to contact with the interior cylindrical wall thereof, friction producing material fixed to one of the contacting surfaces, motor driven means for moving said disc in a path concentric to said cup while maintaining the contact therewith, and means for preventing rotation of said disc, said last mentioned means consisting of a plurality of pins extending into openings in said disc and mounted in an element coaxial with said cup and means for rotating said element whereby to rotate said cup, disc, and element as a unit and means for fixing the said element against rotation.

2. In combination with a slide-moving rack of a machine tool, a pinion and drive therefor, said pinion drive consisting of a shaft carrying said pinion and fixed axially to a cylindrical cup, a disc within said cup and eccentric thereto and arranged to contact with the interior cylindrical Wall thereof, friction producing material fixed to one of the contacting surfaces, motor driven means for moving said disc in a path concentric to said cup while maintaining the contact therewith and means for preventing rotation of said disc, saidlast mentioned means consisting of a plurality of pins extending into openings'in said disc and mounted in an element coaxial with said cup and means for rotating said element whereby to rotate said cup, disc, and element as a unit and meansfor'fixin'g the'said element against rotation.

' OSCAR E. ROSEN. 

